A Tiered Vaccine Framework: Prioritizing Tier 1 Vaccines to Restore Public Confidence

The term "vaccine" has been broadly and inconsistently applied to a range of products with widely divergent immunological outcomes, leading to the erosion of public trust and confusion among both medical professionals and the public. Historically, and by broad public understanding, a vaccine is expected to prevent infection, transmission, and disease through the induction of sterilizing, or true neutralizing immunity, specifically, the prevention of pathogen entry and replication in vivo. This ideal extends beyond the mere elicitation of neutralizing antibodies demonstrable in vitro. This paper proposes a three-tier classification system designed to differentiate products currently designated as "vaccines," specifically to address the distinction between those that meet the traditional, highest-expectation definition (Tier 1), therapeutic vaccines that primarily prevent disease (Tier 2), and immunomodulatory therapeutics that primarily reduce disease severity (Tier 3). By detailing the mechanism of action of each product and emphasizing the urgent need for this refined classification, our aim is to restore public confidence in vaccination programs, improve understanding of vaccine-induced immunity among healthcare professionals, and empower informed decision-making by the public. We argue that a clearer understanding of vaccine capabilities will ultimately lead to increased vaccine uptake for those vaccines that do prevent infection, transmission, and disease.